Pneumonia - Prevention

Studies on vitamin E specifically have been largely negative. A 2002 study reported a higher incidence and greater severity of respiratory infections in older adults who took 200 mg of vitamin E daily.

FactorsThat Lower The Risk for Respiratory Infections

Breastfeeding. Some evidence suggests that women who breastfeed reduce the risk of respiratory infections in their children.

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Low Stress and Active Social Life. Several studies have reported that socially active people with low stress have fewer colds than people who have high stress levels or those who have low stress and few social connections.

Zinc

Zinc appears to have certain important effects on the immune system ,and it may have a direct effect on viruses. Zinc preparations in lozenge or nasal gel form are now available as cold treatments. However, research findings regarding zinc's benefits have varied. (The differing results may be due to different zinc preparations.)

A nasal gel (Zicam), which contains zinc gluconate, has shown some success, possibly because the gel sticks to the nasal passages long enough for the zinc to interact with the virus. In a 2003 study, patients who took the nasal gel within 14 to 48 hours of getting sick had less severe symptoms and felt better faster than those who took a placebo. The finding supports earlier studies reporting thatZicam shortened the duration of a cold by about two days.
Zinc lozenges are showing mixed results. One 2000 study suggested that the use of zinc acetate lozenges (e.g., Fast-Dry, Galzin) may be more effective and have a better taste than other formulations, such as zinc gluconate (Cold-Eeze, Orazinc). On the other hand, a 2002 study reported that zinc gluconate reduced cold duration significantly. To further confuse matters, the two zinc lozenge preparations were directly compared in a 2000 study, and neither was effective. The reasons for these conflicting results are not clear.
A small 2001 study on a nasal spray preparation found no benefits. The spray preparation had less zinc than the nasal gel.

In any case, no one with an adequate diet and a healthy immune system should take zinc for prolonged periods for preventing colds.

Side Effects of Zinc. Side effects include:

Dry mouth.
Constipation.
Nausea.
Bad taste (possibly only with zinc gluconate lozenges).
Overdose may cause severe vomiting, dehydration, and restlessness. Call a physician if any of these symptoms occur.
In rare cases, an allergic response may occur.

Food and Drug Interactions. Zinc may also interact with drugs or other elements.

It may reduce absorption of certain antibiotics.
Foods high in calcium or phosphorus may reduce zinc absorption.
In high doses and for long periods of time zinc can cause copper deficiencies.

Herbs and Supplements

Herbal remedies and dietary supplements are not regulated by the FDA. This means that manufacturers and distributors do not need FDA approval to sell their products. In addition, any substance that affects the body's chemistry can, like any drug, produce side effects that may be harmful. There have been a number of reported cases of serious and even deadly side effects from herbal products.

The following are special concerns for people taking natural remedies for colds:

Echinacea. The herbal remedy echinacea is commonly taken to prevent onset and ease symptoms of cold or flu. Studies have been mixed on its effectiveness. It is difficult to test, however, since it is available in different species (notably, E. purpurea and E. augustifolio) and preparations vary from using extracts to dried forms of just the root, the herb, or the whole plant. If echinacea is helpful at all, it may be more effective taken before symptoms develop than during the cold or flu. However, evidence suggests that it is not helpful at all. In addition, allergic reactions have been reported. People with autoimmune diseases or who have plant allergies should particularly avoid it. There have also been some reports of a reaction called erythema nodosum associated with echinacea. This involves a rash, sometimes accompanied by fever, headache, muscle and joint aches, and sore throat.
Grapeseed extract is sometimes touted as a natural antihistamine. A 2002 study, however, reported no benefits from it.
Chinese herbal cold and allergy medications may contain trace amounts of aristolochic acid, a chemical that is toxic to the kidneys and a carcinogen. Products containing aristolochic acid have been associated with several reports of kidney failure in Europe. Of specific concern are studies suggesting that up to 30% of herbal patent remedies imported from China having been laced with potent pharmaceuticals such as phenacetin and steroids. Most reported problems occur in herbal remedies imported from Asia, with one study reporting a significant percentage of such remedies containing toxic metals.